4.4BSD/usr/src/sys/vm/vm_page.c
/*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vm_page.c 8.1 (Berkeley) 6/11/93
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Authors: Avadis Tevanian, Jr., Michael Wayne Young
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* Resident memory management module.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_pageout.h>
/*
* Associated with page of user-allocatable memory is a
* page structure.
*/
queue_head_t *vm_page_buckets; /* Array of buckets */
int vm_page_bucket_count = 0; /* How big is array? */
int vm_page_hash_mask; /* Mask for hash function */
simple_lock_data_t bucket_lock; /* lock for all buckets XXX */
queue_head_t vm_page_queue_free;
queue_head_t vm_page_queue_active;
queue_head_t vm_page_queue_inactive;
simple_lock_data_t vm_page_queue_lock;
simple_lock_data_t vm_page_queue_free_lock;
/* has physical page allocation been initialized? */
boolean_t vm_page_startup_initialized;
vm_page_t vm_page_array;
long first_page;
long last_page;
vm_offset_t first_phys_addr;
vm_offset_t last_phys_addr;
vm_size_t page_mask;
int page_shift;
/*
* vm_set_page_size:
*
* Sets the page size, perhaps based upon the memory
* size. Must be called before any use of page-size
* dependent functions.
*
* Sets page_shift and page_mask from cnt.v_page_size.
*/
void vm_set_page_size()
{
if (cnt.v_page_size == 0)
cnt.v_page_size = DEFAULT_PAGE_SIZE;
page_mask = cnt.v_page_size - 1;
if ((page_mask & cnt.v_page_size) != 0)
panic("vm_set_page_size: page size not a power of two");
for (page_shift = 0; ; page_shift++)
if ((1 << page_shift) == cnt.v_page_size)
break;
}
/*
* vm_page_startup:
*
* Initializes the resident memory module.
*
* Allocates memory for the page cells, and
* for the object/offset-to-page hash table headers.
* Each page cell is initialized and placed on the free list.
*/
void vm_page_startup(start, end)
vm_offset_t *start;
vm_offset_t *end;
{
register vm_page_t m;
register queue_t bucket;
vm_size_t npages;
int i;
vm_offset_t pa;
extern vm_offset_t kentry_data;
extern vm_size_t kentry_data_size;
/*
* Initialize the locks
*/
simple_lock_init(&vm_page_queue_free_lock);
simple_lock_init(&vm_page_queue_lock);
/*
* Initialize the queue headers for the free queue,
* the active queue and the inactive queue.
*/
queue_init(&vm_page_queue_free);
queue_init(&vm_page_queue_active);
queue_init(&vm_page_queue_inactive);
/*
* Calculate the number of hash table buckets.
*
* The number of buckets MUST BE a power of 2, and
* the actual value is the next power of 2 greater
* than the number of physical pages in the system.
*
* Note:
* This computation can be tweaked if desired.
*/
if (vm_page_bucket_count == 0) {
vm_page_bucket_count = 1;
while (vm_page_bucket_count < atop(*end - *start))
vm_page_bucket_count <<= 1;
}
vm_page_hash_mask = vm_page_bucket_count - 1;
/*
* Allocate (and initialize) the hash table buckets.
*/
vm_page_buckets = (queue_t) pmap_bootstrap_alloc(vm_page_bucket_count
* sizeof(struct queue_entry));
bucket = vm_page_buckets;
for (i = vm_page_bucket_count; i--;) {
queue_init(bucket);
bucket++;
}
simple_lock_init(&bucket_lock);
/*
* Truncate the remainder of physical memory to our page size.
*/
*end = trunc_page(*end);
/*
* Pre-allocate maps and map entries that cannot be dynamically
* allocated via malloc(). The maps include the kernel_map and
* kmem_map which must be initialized before malloc() will
* work (obviously). Also could include pager maps which would
* be allocated before kmeminit.
*
* Allow some kernel map entries... this should be plenty
* since people shouldn't be cluttering up the kernel
* map (they should use their own maps).
*/
kentry_data_size = MAX_KMAP * sizeof(struct vm_map) +
MAX_KMAPENT * sizeof(struct vm_map_entry);
kentry_data = (vm_offset_t) pmap_bootstrap_alloc(kentry_data_size);
/*
* Compute the number of pages of memory that will be
* available for use (taking into account the overhead
* of a page structure per page).
*/
cnt.v_free_count = npages = (*end - *start + sizeof(struct vm_page))
/ (PAGE_SIZE + sizeof(struct vm_page));
/*
* Record the extent of physical memory that the
* virtual memory system manages.
*/
first_page = *start;
first_page += npages*sizeof(struct vm_page);
first_page = atop(round_page(first_page));
last_page = first_page + npages - 1;
first_phys_addr = ptoa(first_page);
last_phys_addr = ptoa(last_page) + PAGE_MASK;
/*
* Allocate and clear the mem entry structures.
*/
m = vm_page_array = (vm_page_t)
pmap_bootstrap_alloc(npages * sizeof(struct vm_page));
/*
* Initialize the mem entry structures now, and
* put them in the free queue.
*/
pa = first_phys_addr;
while (npages--) {
m->flags = 0;
m->object = NULL;
m->phys_addr = pa;
#ifdef i386
if (pmap_isvalidphys(m->phys_addr)) {
queue_enter(&vm_page_queue_free, m, vm_page_t, pageq);
} else {
/* perhaps iomem needs it's own type, or dev pager? */
m->flags |= PG_FICTITIOUS | PG_BUSY;
cnt.v_free_count--;
}
#else /* i386 */
queue_enter(&vm_page_queue_free, m, vm_page_t, pageq);
#endif /* i386 */
m++;
pa += PAGE_SIZE;
}
/*
* Initialize vm_pages_needed lock here - don't wait for pageout
* daemon XXX
*/
simple_lock_init(&vm_pages_needed_lock);
/* from now on, pmap_bootstrap_alloc can't be used */
vm_page_startup_initialized = TRUE;
}
/*
* vm_page_hash:
*
* Distributes the object/offset key pair among hash buckets.
*
* NOTE: This macro depends on vm_page_bucket_count being a power of 2.
*/
#define vm_page_hash(object, offset) \
(((unsigned)object+(unsigned)atop(offset))&vm_page_hash_mask)
/*
* vm_page_insert: [ internal use only ]
*
* Inserts the given mem entry into the object/object-page
* table and object list.
*
* The object and page must be locked.
*/
void vm_page_insert(mem, object, offset)
register vm_page_t mem;
register vm_object_t object;
register vm_offset_t offset;
{
register queue_t bucket;
int spl;
VM_PAGE_CHECK(mem);
if (mem->flags & PG_TABLED)
panic("vm_page_insert: already inserted");
/*
* Record the object/offset pair in this page
*/
mem->object = object;
mem->offset = offset;
/*
* Insert it into the object_object/offset hash table
*/
bucket = &vm_page_buckets[vm_page_hash(object, offset)];
spl = splimp();
simple_lock(&bucket_lock);
queue_enter(bucket, mem, vm_page_t, hashq);
simple_unlock(&bucket_lock);
(void) splx(spl);
/*
* Now link into the object's list of backed pages.
*/
queue_enter(&object->memq, mem, vm_page_t, listq);
mem->flags |= PG_TABLED;
/*
* And show that the object has one more resident
* page.
*/
object->resident_page_count++;
}
/*
* vm_page_remove: [ internal use only ]
* NOTE: used by device pager as well -wfj
*
* Removes the given mem entry from the object/offset-page
* table and the object page list.
*
* The object and page must be locked.
*/
void vm_page_remove(mem)
register vm_page_t mem;
{
register queue_t bucket;
int spl;
VM_PAGE_CHECK(mem);
if (!(mem->flags & PG_TABLED))
return;
/*
* Remove from the object_object/offset hash table
*/
bucket = &vm_page_buckets[vm_page_hash(mem->object, mem->offset)];
spl = splimp();
simple_lock(&bucket_lock);
queue_remove(bucket, mem, vm_page_t, hashq);
simple_unlock(&bucket_lock);
(void) splx(spl);
/*
* Now remove from the object's list of backed pages.
*/
queue_remove(&mem->object->memq, mem, vm_page_t, listq);
/*
* And show that the object has one fewer resident
* page.
*/
mem->object->resident_page_count--;
mem->flags &= ~PG_TABLED;
}
/*
* vm_page_lookup:
*
* Returns the page associated with the object/offset
* pair specified; if none is found, NULL is returned.
*
* The object must be locked. No side effects.
*/
vm_page_t vm_page_lookup(object, offset)
register vm_object_t object;
register vm_offset_t offset;
{
register vm_page_t mem;
register queue_t bucket;
int spl;
/*
* Search the hash table for this object/offset pair
*/
bucket = &vm_page_buckets[vm_page_hash(object, offset)];
spl = splimp();
simple_lock(&bucket_lock);
mem = (vm_page_t) queue_first(bucket);
while (!queue_end(bucket, (queue_entry_t) mem)) {
VM_PAGE_CHECK(mem);
if ((mem->object == object) && (mem->offset == offset)) {
simple_unlock(&bucket_lock);
splx(spl);
return(mem);
}
mem = (vm_page_t) queue_next(&mem->hashq);
}
simple_unlock(&bucket_lock);
splx(spl);
return(NULL);
}
/*
* vm_page_rename:
*
* Move the given memory entry from its
* current object to the specified target object/offset.
*
* The object must be locked.
*/
void vm_page_rename(mem, new_object, new_offset)
register vm_page_t mem;
register vm_object_t new_object;
vm_offset_t new_offset;
{
if (mem->object == new_object)
return;
vm_page_lock_queues(); /* keep page from moving out from
under pageout daemon */
vm_page_remove(mem);
vm_page_insert(mem, new_object, new_offset);
vm_page_unlock_queues();
}
/*
* vm_page_alloc:
*
* Allocate and return a memory cell associated
* with this VM object/offset pair.
*
* Object must be locked.
*/
vm_page_t vm_page_alloc(object, offset)
vm_object_t object;
vm_offset_t offset;
{
register vm_page_t mem;
int spl;
spl = splimp(); /* XXX */
simple_lock(&vm_page_queue_free_lock);
if (queue_empty(&vm_page_queue_free)) {
simple_unlock(&vm_page_queue_free_lock);
splx(spl);
return(NULL);
}
queue_remove_first(&vm_page_queue_free, mem, vm_page_t, pageq);
cnt.v_free_count--;
simple_unlock(&vm_page_queue_free_lock);
splx(spl);
VM_PAGE_INIT(mem, object, offset);
/*
* Decide if we should poke the pageout daemon.
* We do this if the free count is less than the low
* water mark, or if the free count is less than the high
* water mark (but above the low water mark) and the inactive
* count is less than its target.
*
* We don't have the counts locked ... if they change a little,
* it doesn't really matter.
*/
if (cnt.v_free_count < cnt.v_free_min ||
(cnt.v_free_count < cnt.v_free_target &&
cnt.v_inactive_count < cnt.v_inactive_target))
thread_wakeup((int)&vm_pages_needed);
return (mem);
}
/*
* vm_page_free:
*
* Returns the given page to the free list,
* disassociating it with any VM object.
*
* Object and page must be locked prior to entry.
*/
void vm_page_free(mem)
register vm_page_t mem;
{
vm_page_remove(mem);
if (mem->flags & PG_ACTIVE) {
queue_remove(&vm_page_queue_active, mem, vm_page_t, pageq);
mem->flags &= ~PG_ACTIVE;
cnt.v_active_count--;
}
if (mem->flags & PG_INACTIVE) {
queue_remove(&vm_page_queue_inactive, mem, vm_page_t, pageq);
mem->flags &= ~PG_INACTIVE;
cnt.v_inactive_count--;
}
if (!(mem->flags & PG_FICTITIOUS)) {
int spl;
spl = splimp();
simple_lock(&vm_page_queue_free_lock);
queue_enter(&vm_page_queue_free, mem, vm_page_t, pageq);
cnt.v_free_count++;
simple_unlock(&vm_page_queue_free_lock);
splx(spl);
}
}
/*
* vm_page_wire:
*
* Mark this page as wired down by yet
* another map, removing it from paging queues
* as necessary.
*
* The page queues must be locked.
*/
void vm_page_wire(mem)
register vm_page_t mem;
{
VM_PAGE_CHECK(mem);
if (mem->wire_count == 0) {
if (mem->flags & PG_ACTIVE) {
queue_remove(&vm_page_queue_active, mem, vm_page_t,
pageq);
cnt.v_active_count--;
mem->flags &= ~PG_ACTIVE;
}
if (mem->flags & PG_INACTIVE) {
queue_remove(&vm_page_queue_inactive, mem, vm_page_t,
pageq);
cnt.v_inactive_count--;
mem->flags &= ~PG_INACTIVE;
}
cnt.v_wire_count++;
}
mem->wire_count++;
}
/*
* vm_page_unwire:
*
* Release one wiring of this page, potentially
* enabling it to be paged again.
*
* The page queues must be locked.
*/
void vm_page_unwire(mem)
register vm_page_t mem;
{
VM_PAGE_CHECK(mem);
mem->wire_count--;
if (mem->wire_count == 0) {
queue_enter(&vm_page_queue_active, mem, vm_page_t, pageq);
cnt.v_active_count++;
mem->flags |= PG_ACTIVE;
cnt.v_wire_count--;
}
}
/*
* vm_page_deactivate:
*
* Returns the given page to the inactive list,
* indicating that no physical maps have access
* to this page. [Used by the physical mapping system.]
*
* The page queues must be locked.
*/
void vm_page_deactivate(m)
register vm_page_t m;
{
VM_PAGE_CHECK(m);
/*
* Only move active pages -- ignore locked or already
* inactive ones.
*/
if (m->flags & PG_ACTIVE) {
pmap_clear_reference(VM_PAGE_TO_PHYS(m));
queue_remove(&vm_page_queue_active, m, vm_page_t, pageq);
queue_enter(&vm_page_queue_inactive, m, vm_page_t, pageq);
m->flags &= ~PG_ACTIVE;
m->flags |= PG_INACTIVE;
cnt.v_active_count--;
cnt.v_inactive_count++;
if (pmap_is_modified(VM_PAGE_TO_PHYS(m)))
m->flags &= ~PG_CLEAN;
if (m->flags & PG_CLEAN)
m->flags &= ~PG_LAUNDRY;
else
m->flags |= PG_LAUNDRY;
}
}
/*
* vm_page_activate:
*
* Put the specified page on the active list (if appropriate).
*
* The page queues must be locked.
*/
void vm_page_activate(m)
register vm_page_t m;
{
VM_PAGE_CHECK(m);
if (m->flags & PG_INACTIVE) {
queue_remove(&vm_page_queue_inactive, m, vm_page_t,
pageq);
cnt.v_inactive_count--;
m->flags &= ~PG_INACTIVE;
}
if (m->wire_count == 0) {
if (m->flags & PG_ACTIVE)
panic("vm_page_activate: already active");
queue_enter(&vm_page_queue_active, m, vm_page_t, pageq);
m->flags |= PG_ACTIVE;
cnt.v_active_count++;
}
}
/*
* vm_page_zero_fill:
*
* Zero-fill the specified page.
* Written as a standard pagein routine, to
* be used by the zero-fill object.
*/
boolean_t vm_page_zero_fill(m)
vm_page_t m;
{
VM_PAGE_CHECK(m);
m->flags &= ~PG_CLEAN;
pmap_zero_page(VM_PAGE_TO_PHYS(m));
return(TRUE);
}
/*
* vm_page_copy:
*
* Copy one page to another
*/
void vm_page_copy(src_m, dest_m)
vm_page_t src_m;
vm_page_t dest_m;
{
VM_PAGE_CHECK(src_m);
VM_PAGE_CHECK(dest_m);
dest_m->flags &= ~PG_CLEAN;
pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m));
}